Drawing instrument.



Patented Apr. 10,.' 1000.

N. -MsHuu's DRAWING 'INSTRUMENL (Application mea Jan. a0, 1599.)

2 Sheets-Sheet l.-

(N0 Nudel.)

7'//T/////// /%/I/// //////////////////////////////////Z No. 647,064. Patented Apr. I0, i900.

N. BAASHUUS.

DRAWING lNSTRUMENT.

(Application led Jan. 30, 1899.)

2 Sheets-Sheet 2.

(lo Maciel.)

rrrnn STATES NILS BAASHUUS, OF CHARLOTTENBURG, GERMANY;

bRAwlNc INSTRUMENT.

srncrrrcATIoN Vlaming part of Letters Patent Nt. 647,064, dated April 1o, 1906; Application' filed January so, 1899. serial No. 703,9@l (N6 titan T0 tu whom, t may-'concerns Be it known that I, NILs BAAsHUUs, engineer, of Charlottenburg, near Berlin, in the Empire of Germany, have invented Improvements in Drawing Instruments, of which the following is a specification.

The present invention relates to an improved drawing instrument consisting of two parts applied to an ordinary T-square. The instrument so constructed forms acheap and convenient beam-compass which may be accurately and readily adjusted even for the largest radii by a single draftsman.

On the accompanying drawings, Figure l shows a view of the complete instrument in position for use. Fig. 2 shows a vertical section of the T-square with carrying device for the pen or pencil point attached. Fig. 3 is an edge view of the T-square, partly broken away, with center point and pen or pencil point attached. Fig. 4 is a plan view of the same. Fig. 5 shows a vertical section of a simpler form of the carrier g2 applied to a T- square, and Fig. 6 shows the simplest form of carrier g3.

To describe large circles, the T-square ct b is laid upon the `drawing-paper c with its under side upward, the center point'cl screwed to the head c, and the adjustable device e, carrying the pen or the blade h.

For the purpose of protecting the blade of the T-square a plate f, Fig. 2, is inserted between it and the set-screw. The device for holding the pen or pencil point consists of a sliding carrier g, embracing the blade b by means of three Shanks 7i h t'. The carrier g has at its top a guide 7c for the pen or pencil point holder l, having a micrometer-screw m of ordinary construction for very accurate adj ustment. The threaded portion of this screw passes through the parts g l and is secured at its farther end. When, therefore, the screw is turned, the part Z is caused to travel along on the screw, which is secured to the top portion of the carrier g. The holder Z is provided with a pointer n, and the top portion of the carrier g has a scale engraved upon it, on which the divisions can be read off. The zero-point of the scale corresponds with the central'position of the pen or pencil point, and the scale reads outwardly on each side. The

pencil point, screwed to' pen or pencil point w is vertically adjustable in the guidewaypJ p, and a spiral spring holds the pen or pencil point at a suitable distance from the paper. In drawingl the point is depressed vertically by means of the iin ger or other appropriate device. The point w permits of being drawn out from above for the purpose of cleaning, filling, sharpening, or the like. To prevent the point w' turning in its guidewaypp, a slot is provided in it, into which passes a set-screw r. By tightening up this screw the pen or pencil point can be held at any vertical height.

The distances A A and B B' are precisely equal-that is, the devices for carrying center point and pen or pencil point are so constructed that the center of each lies in a line parallel to the edge :c of the blade b. The radius to be described can thus be directly marked off on the blade h and the pen or pencil point adjusted accordingly. The distance A A2 is likewise equal to the distance B 132-- t'. e., the distance from the edge B2 'to the pen or pencil point when the latter is in its central position. Thus instead of the distance between center point and the pen or pencil point the equal distance between A2 and B2 may be read off.

Fig. 5 shows a less elaborate form of the invention for use when exact adjustment to small fractions of a millimeter is not of inoment. Here the micrometersscrew is dispensed with and the carrier g2 formed in one with the holder Z2 for the pen or pencil point. All adjustments of the pen or pencil point are then eifected by means of the whole carrying device g2, which when the desired distance has been measured off between the center point and the pen or pencil point is secured to the blade by the setscrew c.

In the form shown in Fig. 5 the guard-plate f, Figs. 2 to 4, is also dispensed with, the pressure on the blade being of little consequence if the screw U is of adequate diameter.

Fig. 6 shows an extremely simple form of the invention. The holder Z3 is constructed in one piece with the carrier g3 and is formed with a simple cylindrical head for the point w3. The arrangement of the shanks and setscrew is the same as in Fig. -5.

An instrument constructed in accordance with thepresent invention possesses inani- IOO fold advantages over ordinary beam-compasses.

First. A special beam is dispensed with, an ordinary T-square, which every draftsman has always at hand, being used instead.

Second. The use of a T-square as beam prevents the instrument tipping over by reason of the broad surface presented to the paper. By this means even with the largest radii the instrument can be accurately and readily manipulated by a single draftsman.

Third. The center point and pen or pencil point lie on a line parallel to the edge of the T-square blade, and the distance from lthe center point to the pen or pencil point (when the pointeris at zero-point on the micrometerscale) is equal to the distance from the edge A2 to the edge B2. Thus by laying the scale against the edge A2 of the device carrying the center point and measuring off by the edge B2 radii can readily be set olf. There is thus the advantage of being able to adjust edges instead of points.

The pen or pencil point is vertically adjustable, so that the inconvenience of having to raise the Whole apparatus from the paper at the part where marking is taking place is obviated. The arrangement also facilitates the operations of cleaning, filling, and sharpening the pen or pencil point.

stantially as described, and for the purposes hereinbefore set forth.

2. A drawing instrument consisting of a T- square a b,- a device d carrying a center point attached to the head a of said T-square, and a device e carrying a vertically-adj ustable pen or pencil or like point w attached to the blade b of said T-square, and comprising a carrier g having Shanks 77. h 'L' and a set-screw o and protection-platef, a guide 7c with micrometerscale and a holder l for the point w provided With a micrometer-screw m, a spi-ral spring q, a pointer n and aset-screw rscrewing through the said holder l and passing into a slot in the point w, all substantially as and for the purposes hereinbefore set forth.

In Witness whereof I have hereunto set my hand in presence of two Witnesses.

NILS BAASHUUS.

NVitnesses:

WOLDEMAR HAUPT, ERWIN' L. GoLDsoHMID'r. 

